In some applications, particularly band pass filters, discriminators, and the like, it is desirable to have highly stable devices for passing or selecting signals having predetermined frequencies while dissipating or rejecting any remaining signals with different frequencies. In prior art devices this is accomplished through the use of monolithic crystal filters, which include several acoustic resonators on a single substrate acoustically coupled by bulk acoustic waves. However, monolithic crystal filters are relatively complicated to fabricate and are relatively expensive. Further, it is relatively complicated to produce several acoustic resonators, resonant at different frequencies, on a single substrate.